North American Philips Corporation

Ted A Darby

Saiprasad V Naimpally

Larry G Phillips

Anthony R Bugni

William S Burdick

In order to obtain the benefits of benefits of field and frame recursive noise reduction while reducing the detriments thereof, a circuit arrangement includes a motion compensated frame recursive noise reduction circuit and a motion compensated field recursive noise reduction circuit. The outputs of these two noise reduction circuits are then combined. The motion compensation vectors for the field and frame recursive noise reduction circuits are determined such that in the case of little or no detected motion, the system is biased toward frame recursive noise reduction to achieve the best resolution on still and slow moving scenes. While in the case of increased motion, the circuit reverts more to field recursive noise reduction to reduce smearing.

Method and apparatus for combining field and frame recursive noise

A television receiver includes a motion detection circuit which compares corresponding portions of the picture signal from adjacent fields or frames and based on this comparison generates movement signals. In addition, the television receiver includes a noise measurement circuit which compares corresponding portions of succeeding scanning lines, these corresponding portions having identical contents with the exception of any added noise, accumulates the results of these comparisons, and output the accumulated results at the end of each field as a noise signal. The motion signals and the noise signal are then applied as control signals to an adjustable noise reduction circuit for reducing the noise content in the television signal.

Video noise reduction system with measured noise input

A T.V. input source identifying circuit for determining whether a video signal is from a videotape player or a broadcast signal by measuring jitter of vertical synchronization pulses and by measuring noise. The video signal includes a plurality of frames with each frame including a plurality of fields. In one embodiment of the present invention, timing data is generated corresponding to the period of at least one selected field in each of a plurality of selected frames. From this timing data, a maximum number is stored that corresponds to the greatest period and a minimum number is stored that corresponds to the least period of the selected fields. The minimum number is subtracted from the maximum number and the difference is compared to a threshold to determine the type of video signal. In an alternate embodiment, numbers corresponding to fields from successive frames are compared by a subtraction and the difference is compared to a threshold in order to make a decision as to the type of video signal. In both of the aforementioned embodiments, the noise level of the video signal is constantly monitored. When the noise is above a threshold, the local signal is generated regardless of the information derived from the timing data.

T.V. input source identifier responsive to jitter and noise

The present invention discloses a noise measurement method and system in a television signal receiver. In the preferred embodiment, the receiver has a noise reduction circuit and receives a composite television picture signal which contains noise, picture information, a trigger pulse (preferably the V-sync pulse), a horizontal synchronizing pulse (at least once per television scan line) and a standard signal adjacent in time to and later than the horizontal synchronizing pulse. The preferred standard signal is a back porch signal or a color burst signal. A comparator receives at least two samples of the standard signal and produces a comparison signal that is representative of the comparison of the two standard signal samples. Preferably the two standard signal samples are from two different scan lines. An accumulator circuit receives the comparison signal and generates a measured noise signal that is used to control the noise reduction circuit.

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Knoxville, TN, United States of America

Ted A Darby